This is an improvement on my U.S. Pat. No. 4,349,143 issued Sept. 14, 1982. In that patent, provision was made for the stapling tool to have two power settings. The high setting produced relatively more power to drive the staples into hard materials, and the low setting produced relatively less power to keep from driving the staples through thin or soft material. In order to produce the high and the low power, the solenoid had two coils that could be jointly or singly energized. This permitted a selection between the high-force operation and the low-force operation.
Obviously, the use of two solenoid coils is a relatively expensive way to provide this selective power feature. It is the object of the present invention to permit the operator to select the high or the low power setting while using but a single coil which will reduce manufacturing costs and reduce tool size in comparison with the dual coil arrangement shown in my prior patent.